Porous polymers

ABSTRACT

This invention provides a highly porous crosslinked functionalised polymer having interconnected cavities of micron dimensions and having a pore volume greater than about 5.6 cc/g and having a capacity to absorb water and also to absorb saline solutions. The polymers are generally based on styrene or various acrylates or mixtures and have a functional group selected from a large range of ionic and polar compositions.

This is a divisional application of Ser. No. 707,279 filed Mar. 1, 1985U.S. Pat. No. 4,612,334.

This invention relates to porous polymeric materials; more particularlyto crosslinked polymeric materials of high absorbency and to methods fortheir production and chemical modification from low density polymers. InEuropean Patent Application No. 60 138 novel crosslinked polymers havebeen disclosed which are of unusually low density and high porosity.

A technique for their preparation employing a novel high internal phaseemulsion polymerisation system has been disclosed and various monomershave been employed in the production of these porous polymers.

In view of the interesting properties exhibited by these porous polymersfurther work has been done on evaluating alternative monomers in anattempt to introduce chemically active groupings into the porous polymerwhich, together with the polymer structure, allow the preparation ofporous polymers having useful physical and chemical characteristics.

More particularly by selection of the appropriate functional groups anddrying environment specialised absorbents and carriers can be produced.

The materials provided by this invention comprise a family of closelyrelated highly porous crosslinked functionalised polymers crosslinkedfrom 1-20% and having interconnected cavities or chambers of microndimensions whose total pore volume is greater than 5.6 cc/gm in itssolvent swollen state and having a capacity for spontaneous waterabsorption from its dry state of at least 3 g liquid per gram of polymerand having a capacity for saline absorption (10% NaCl) such that theratio of saline to water absorption is greater than 0.1, preferablygreater than 0.5 and most preferably greater than 0.7, said polymercomprising structural units ##STR1## in which A represents a crosslinkedcarbon chain, Y is an optional spacer group and Z is an ionic or polarfunctional group, selected from lower alkyl cationic nitrogen species,lower alkyl amine oxide, alkoxylate, a metal or ammonium or substitutedsalt of a sulphuric, carboxylic, phosphoric or sulphonic acid group or amixture of such groups, except that where Z is a sulphonic acid Y doesnot represent ##STR2##

Preferably, A represents a saturated, crosslinked carbon chain havingthe structure: ##STR3## where R is hydrogen or methyl group. Y is anoptional spacer group, especially ##STR4## where m=0 to 5 (preferablym=0 or 1).

Z represents a single or mixture of ionic or polar functional groups ofstructures 1-3 ##STR5## where R₂, R₃ and R₄ are short chain alkyl orcycloalkyl or aryl or hydroxyalkyl or where R₂ and R₃ form part of aring system and where R₂, R₃ and R₄ may be the same or different,provided that the total number of carbon atoms in R₂ +R₃ +R₄ is lessthan 10 for the cationic species (I) or provided that the total numberof carbons in R₂ +R₃ is less than 8 for the amine salts (2) and amineoxides (3) and where X⁻, the counterion, may be an inorganic speciesselected from chloride, sulphate or nitrate or a lower organic (<C₈)carboxylate species such as acetate or lactate, but may also behydroxide with the cationic species (I). Z may also represent analkoxylated chain of the type: ##STR6## where p is 1 to 680, and##STR7## and where R₅ is a hydrogen or a short alkyl group and M is ametal, ammonium or substituted ammonium cation. Especially preferred isR₅ =hydrogen, B=CH₂ OH and p<20.

In a further preferred form of the invention, A represents a linearsaturated crosslinked carbon chain of the type: ##STR8## where R₁ isagain hydrogen or methyl and Z is attached directly to the chain A. Thegroup Z can be any of those described above but especially preferred isthe metal, ammonium or substituted ammonium salt of a carboxylic acid,where the carboxylated monomers constitute at least 75% of the totalmonomer composition.

Alternatively, A can represent an unsaturated crosslinked carbon chainderived from a diene monomer, or a mixture of carbon chain systems.

The level of crosslinking agent can be from 1-20% or more, preferably2-10%. At crosslinking levels less than 1%, the polymers are soft gelsin their solvent swollen state and are unable to support their ownsolvent swollen weight. Moreover, at crosslinking levels of 2% or less,the polymers are prone to structural collapse during the drying processunless great care is exercised in the choice of drying conditions.

At crosslinking levels of 15-20% or greater, shrinkage of the polymerduring drying and re-swelling during solvent absorption is eliminatedbecause the polymer chains are immobilised by the crosslinking agent.However, the polymers will still have a water absorbency >3 g/g andsaline/water absorption ratio >0.1, especially at the higher degrees ofsubstitution (>40%, preferably >70%). Optimum polymer absorption occursat crosslinking levels between 2-10% as a compromise between mechanicalstrength and polymer mobility and swelling.

Pore volume should be greater than 85% (5.6 cc/g) of polymer volume andpreferably greater than 95% (20 cc/g) as the liquid absorption capacityincreases with pore volume. Again liquid absorption capacity isdependent on the pore volume coupled with the levels of crosslinking anddegree of substitution. At lower pore volumes, the crosslinking levelsare preferably in the lower range (2-10%) and the level of substitutionin the higher range (preferably >70%) for maximum liquid absorption.

The degree of substitution or functionalisation of the polymer is >30%,preferably >50% and most preferably >70%, since the amount of solventimbibed increases with number of ionic or polar functional groupspresent, provided the level of crosslinking does not exceed 15-20%.Above this level of crosslinking, the amount of liquid absorbed becomesmuch less sensitive to the degree of substitution since the liquiduptake is then dependent on the mobility of the solvated polymer chains.

With high degrees of substitution (usually >50%) and lower levels ofcrosslinking (<15%), these ionic or polar polymers generally collapse ondrying from polar solvents, such as methanol or water, into hardgranules, which show a marked visible swelling when liquid absorptiontakes place from the dried state, although such a collapse andre-swelling is not an essential feature of the invention. Thesephysically collapsed materials generally show little affinity fororganic oils which is reflected in their low oleic acid absorptionfigures (see examples). When dried from a non-polar solvent, such ashexane, these polymers may retain a more open expanded, brittlestructure and, in the case of the cationic nitrogen species and aminesalts and amine oxides, may become much less hydrophilic in nature andshow a greater ability to absorb lipophilic oils. In some instances,such as the ethoxylates or with the highly crosslinked polymers or withpolymers having a lower degree of substitution, no physical collapseoccurs on drying from polar solvents so that they retain a greaterability to wick in oleic acid. The ethoxylated polymers are soft,rubbery and elastic.

The absorbent materials provided by this invention are generallyprepared indirectly by chemical modification of a preformed porouspolymer block carrying a reactive group such as a chloromethyl or esterfunctionality. The preformed porous polymers which are suitable forsubsequent chemical modification can be prepared by polymerisation ofsuitable monomers of low water solubility, such as chloromethylstyrene,n-butyl methacrylate, t-butyl acrylate, 2-ethylhexyl acrylate or otherappropriate acrylate or methacrylate esters or their mixtures. Otherco-monomers (including the crosslinking agent) can also be incorporatedat levels up to 20% or more provided that such monomers do notdestabilise the high internal phase emulsion used in the polymerpreparation and provided that the reactive monomer is present at asufficiently high level to enable the final polymer generated afterchemical modification to carry ionic or polar function groups on aminimum of 30% of the monomer residues.

Other suitable monomers which can be used to prepare the highly porouspolymer for subsequent chemical modification are styrene,α-methylstyrene or other substituted styrenes or vinylaromatic monomerswhich, after polymerisation, can be chloromethylated, nitrated orotherwise functionalised to produce a porous polymer intermediate whichcan be subsequently converted to the ionic or polar porous polymers ofthis invention.

Alternatively, the porous polymers carrying the ionic or polarfunctional groups can be prepared directly by emulsification andpolymerisation of the appropriate monomer provided that such a monomercan be formed into a stable and polymerisable high internal phaseemulsion.

This invention also provides a porous, homogeneous, crosslinkedpolymeric material having a dry density of less than 0.15 g/cc andcomprising at least 30% by weight of chloromethyl styrene residuescrosslinked with a di-functional agent such as divinyl benzene.

The chloromethyl styrene polymer is prepared by the general proceduredescribed in European Patent Application No. 60 138.

The method of preparation of the crosslinked chloromethyl styrenepolymer is similar to that of styrene-based porous polymer, although aslightly higher concentration of emulsifier is required to give auniform structure (25% for chloromethyl styrene cf 20% for styrene).

Lower levels of emulsifier give materials which contain some large voids(ca 100 μm) in addition to the typical pore structure (ca 10 μm). Withhigher levels of surfactant the preparation of the emulsion becomes moredifficult and 25% emulsifier is the maximum level which can beincorporated into a 96.5% internal phase emulsion with ease.

2.5 gm Span 80 and 1 cm³ commercial divinyl benzene/ethyl vinyl benzeneare dissolved in 10 cm³ chloromethyl styrene in a polypropylene beaker.0.75 gm potassium persulphate is dissolved in 300 cm³ demineralisedwater and this solution is added dropwise to the stirredmonomer/surfactant mixture. After the addition of the potassiumpersulphate solution is complete the beaker is sealed and heated to 60°C. in a water bath to effect polymerisation. After 18 hours a solidblock of wet polymer is obtained which may be dried in air at 30° to 40°C.

In the examples, the starting substrate was a porous polymer prepared bythe process as described. The polymer was dried and soxhlet extractedwith hexane prior to any chemical transformations, to remove theresidual emulsifier (Span 80), but this is not essential in most cf thechemical modification reactions. Extraction of the emulsifier wascarried out partly to reduce the possibility of unwanted side reactionsand partly to facilitate interpretation of Infra Red Spectra which wereused qualitatively to monitor extents of reaction.

The polyacrylate materials were prepared by hydrolysis of thecorresponding acrylate esters. These acrylate ester polymers wereprepared in a similar manner to that used for chloromethylstyrene withSPAN 80 as emulsifier.

The invention will now be described in greater detail and dataconcerning the new polymers claimed and comparable polymers not withinthe scope of this invention are given in the Tables. Temperatures are°C.

PREPARATION OF CATIONIC NITROGEN DERIVATIVES

Depending on the solubility of the tertiary amine to be employed, wateror ethanol was chosen as solvent for the reaction, although othersolvents could be employed. The preformed chloromethyl styrene porouspolymer was filled with solvent under vacuum in a round bottomed flaskand the desired tertiary amine added (usually 10 times molar excess,although greater or lesser amounts of amine can be used). The reactantswere heated at temperatures between 40° C. and reflux for periodsbetween 3 minutes and 15 hours depending on (a) the reactivity of theamine and (b) the desired extent of reaction. Reaction will take placeat lower temperatures but the reaction times are increased. The cationicproduct was removed from the reaction mixture, washed extensively withwater or ethanol and then methanol to remove unreacted tertiary amine.The solids were then allowed to air dry from the methanol saturatedstate. Alternatively, the methanol saturated polymer could be treatedwith ethyl acetate and then hexane to give a hexane swollen polymerwhich was allowed to air dry. These solids could, if desired, be furtherdried in a vacuum oven at elevated temperatures ( 80° C.). The solidsobtained from methanol were generally collapsed, hard particles, whereasthose obtained from hexane were generally expanded, less dense polymerpieces. The dried solids were then examined for their liquid absorptionproperties. The extents of reaction were quantified using a standardVolhard's estimation for chloride ions (see A I Vogel `A textbook ofQuantitative Organic Analysis` LONGMAN'S 3rd ED 1961 p 267 Sub III 35Proc.B).

    ______________________________________                                        Preparation of Examples Shown in Table 1                                      Example      Preparation                                                      ______________________________________                                        1            Excess aqueous amine, reflux,                                                 30 min with chloromethyl polymer                                 2            Excess ethanolic amine, reflux,                                               25.0 hours with chloromethyl polymer                             3            Excess ethanolic amine, reflux,                                               7.5 hours with chloromethyl polymer                              4            Excess ethanolic amine, reflux,                                               7.0 hours with chloromethyl polymer                              5            Standard porous polymer preparation                              Polystyrene polymer                                                           6            Excess aqueous amine, 45°,                                             3.0 min with chloromethyl polymer                                7            Excess aqueous amine, 50°,                                             3.0 min with chloromethyl polymer                                8            Excess aqueous amine, reflux,                                                 7.0 hours with chloromethyl polymer                              9            OH.sup.- /Cl.sup.-  exchange on Example 8                        10           NO.sub.3.sup.- /Cl.sup.-  exchange on Example 1                  11-13        Excess aqueous amine, 65°,                                             2.0 hours with chloromethyl polymer                              14           Excess aqueous amine, reflux,                                                 7.0 hours with chloromethyl polymer                              ______________________________________                                    

Examples are given in Table I. Here Examples 1 to 4 show that increasingthe N-alkyl chain length decreases the aqueous absorption such that theproducts are unsatisfactory where the total number of carbons in theN-alkyl groups exceeds 10. Example 5 shows that the material disclosedin European Patent Application No. 60 138 also fails our criteria.Examples 6-8 and 1 shows the effect of increasing the degree offunctionalisation of the polymer where the lowest substituted materialis excluded from our invention. Examples 8-10 and 1 show the effect ofthe counterion on the liquid absorption. Examples 11 and 1 show theeffect of pore volume and Examples 12, 13 and 1 show the effect ofcrosslinking level. Table 1B shows the effect of drying the polymersfrom a non-polar solvent, i.e. that the hydrophilicity is reduced andthe lipophilicity is increased relative to the methanol dried samples.

SALTS OF THE AMINO DERIVATIVES

The amine salts are prepared by treating the appropriate amines witheither neat or dilute solutions of the desired mineral or organic acids.Thus, for example, the amines can be treated with methanolic solutionsof hydrochloric acid, aqueous solutions of sulphuric acid or neat lacticor oleic acids. The salts so formed are then washed with solvent untilfree of excess acid and dried.

    __________________________________________________________________________    Preparation of Examples Shown in Table 2                                      Example                                                                             Amine Preparation          Salt Preparation                             __________________________________________________________________________    1     Excess aqueous amine on chloromethyl, reflux, 15 hours                                                   Methanolic HCl on amine                      2     Excess aqueous amine on chloromethyl, 70°, 21                                                     Methanolic HCl on amine                      3     Excess ethanolic amine on chloromethyl, 100°, 11                                                  Methanolic HCl on amine                      4     Standard porous polymer preparation                                     Polystyrene                                                                   polymer                                                                       5     Excess aqueous amine on chloromethyl, 90°, 5                                                      Methanolic HCl on amine                      6     Excess aqueous amine on chloromethyl, 90°, 5                                                      50% H.sub.2 SO.sub.4 /H.sub.2 O on                                            amine                                        7     Excess aqueous amine on chloromethyl, reflux, 15 hours                                                   50% H.sub.2 SO.sub.4 /H.sub.2 O on                                            amine                                        8     Excess aqueous amine on chloromethyl, reflux, 15 hours                                                   100% lactic acid on amine                    9     Excess aqueous amine on chloromethyl, reflux, 15 hours                                                   100% oleic acid on amine                     10,11,13                                                                            Excess aqueous amine on chloromethyl, reflux, 25 hours                                                   Methanolic HCl on amine                      __________________________________________________________________________

Examples are given in Table 2. Examples 1-3 show the effect ofincreasing the number of carbons attached to nitrogen such that theinvention fails with more than 8 carbons. Example 4 again shows thefailure of the materials disclosed in European Patent Application No. 60138. Examples 5-9 and 1 show the effect of the counterion and the effectof increasing level of substitution. Note that Example 9 with the longchain organic counterion fails our criteria. Examples 10 and 1 show theeffect of pore volume. Examples 11-13 show the effect of increasing thedegree of crosslinking. Table 2B again shows the effect of dryingsolvent.

PREPARATION OF THE AMINE OXIDE DERIVATIVES

The amine oxide derivatives were prepared by immersing the amino porouspolymer in 30% hydrogen peroxide solution, using vacuum filling toassist the process. The reactants were then heated at 60° C. for periodsup to 15 hours. The solids were recovered, washed and dried as before.

As with the short alkyl chain cationics and amine salts, the amine oxidederivatives with short chains dried from methanol as collapsed, dense,brittle particles that were hydrophilic and water-swellable. Again,these dried polymers show an equally high affinity for saline solutionsas they do for water but have little desire to absorb oleic acid.

    ______________________________________                                        Preparation of Examples Shown in Table 3                                      Example Preparation                                                           ______________________________________                                        1       Excess 30% aqueous H.sub.2 O.sub.2, 60°, 14 hours on                   amine                                                                 2       Excess 30% aqueous H.sub.2 O.sub.2, 60°, 6 hours on amine      3       Excess 30% aqueous H.sub.2 O.sub.2, 60°, 7 hours on amine      4       Standard porous polymer preparation                                   Polystyrene                                                                   polymer                                                                       5       Excess 30% aqueous H.sub.2 O.sub.2, 60°, 6 hours on amine      6-8     Excess 30% aqueous H.sub.2 O.sub.2, 60°, 10 hours on           ______________________________________                                                amine                                                             

Examples are given in Table 3. Examples 1-3 show the effect ofincreasing carbon number attached to nitrogen so that the inventionfails with more than 8 carbons. Examples 5 and 1 show the effect ofsubstitution level and Examples 6 and 2 show the effect of pore volume.Examples 7, 8 and 2 show the effect of crosslinking level. Table 3Bshows the effect of drying solvent.

PREPARATION OF ALIPHATIC SULPHATE DERIVATIVES

Porous polymers containing aliphatic sulphate groups can be obtained bytreatment of the chloromethyl styrene polymer with the sodium orpotassium salt of acetic acid in dimethyl formamide (DMF) as solvent, atreflux for periods up to 15 hours, to yield the acetoxy derivative.After washing out the DMF, the acetate ester can be hydrolysed inaqueous ethanol at reflux for period up to 15 hours.

The hydroxymethylstyrene polymer so produced can, in principle, besulphated by a number of standard techniques but is preferably sulphatedunder conditions of low acidity such as with sulphur trioxide:aminecomplexes. For example, heating the hydroxymethyl polymer on a steambathfor up to 35 hours with an excess of SO₃ :pyridine complex in DMF assolvent, gives the desired sulphate salt after workup andneutralisation. Two examples of sulphate derivatives with differentdegrees of substitution are given in Table 4 (Examples 1 and 2).

PREPARATION OF ALIPHATIC SULPHONATE DERIVATIVES

A porous polymer containing aliphatic sulphonate groups was obtained byprolonged treatment of the hydrophilic, water-swellable triethylammonium substituted polymer with a solution of sodium sulphite in waterat pH9. The reactants were refluxed for up to 70 hours. The polymericsolids were recovered, washed with water, then methanol and dried togive collapsed, brittle polymer particles that wer hydrophilic and waterswellable. Infra red spectroscopy confirmed that the cationic group wasno longer present and that sulphonate functional groups were nowpresent.

Liquid absorption properties are given in Table 4, where Examples 3 to 5show the effect of substitution level on liquid uptake. Examples 4 and 5(Table 4(A) and (B)) show that the drying solvent has relatively littleeffect on the liquid absorption.

PREPARATION OF CARBOXYLATED POROUS POLYMERS

These can be obtained by a variety of synthetic routes such as two stepoxidation of the chloromethyl derivative. Thus, the chloromethylstyrenepolymer can be oxidised with dimethyl sulphoxide and potassiumbicarbonate at 155° C. for periods up to 21 hours to the aldehydecontaining polymer, which in turn can be oxidised further to thecarboxylic acid with a variety of standard oxidising agents.Alternatively, the chloromethyl styrene polymer or the correspondingalcohol can be oxidised directly to the carboxylic acid using a mixtureof nitric acid and potassium nitrate at 100° C. for period up to 7hours. Alternatively, carboxylic acid containing polymers can beobtained by reaction of the chloromethyl styrene polymer with the anionderived from diethylmalonate, followed by hydrolysis of the estergroupings. These solids in their acidic form are hydrophobic and floaton water at neutral or acidic pH, whereas when placed in water atalkaline pH, they will become hydrophilic and absorb the aqueous liquid.In the form of their sodium salts, the polymers are hydrophilic atneutral pH and will absorb water and sink.

Preferably, the hydroxymethyl polymer is oxidised to the carboxylatewith standard oxidising agents such as nitric acid or alkalinepermanganate, by warming the mixture on a steam bath for up to 1 hourwith permanganate or for up to 6 hours with nitric acid. Under theseconditions, some polymer cleavage can occur and can result in a polymercarrying a higher than expected number of carboxylate functions. Thispolymer cleavage results in some loss of mechanical strength due to theincreased mobility of some polymer segments and, as such, behaves as apolymer of lower crosslinked density. With nitric acid oxidation ofhydroxymethyl and chloromethyl polymers, nitration of the aromatic ringgenerally co-occurs along with oxidation to the carboxylate but thisdoes not detract from the absorption properties of the polymer.

The acrylic and methacrylic carboxylated polymers are prepared from thecorresponding esters by hydrolysis. This can be achieved in aqueoussulphuric acid of between 50 and 90% concentration depending on howresistant the esters are to hydrolysis. At lower temperatures, such asroom temperature, the hydrolysis may require several days but can becarried out over several hours at higher temperatures e.g. 60° C.

Examples are given in Table 4. Examples 6-9 show the effect ofincreasing the degree of carboxylation. Here Examples 8 and 9 are quotedas having 5% crosslinks from the divinyl benzene used in the polymerpreparation but, in reality, the effective crosslinking level isprobably less due to chain cleavage during oxidation. Example 10 showsthe effect of reducing pore volume. Again, Examples 11-13 show theeffect of increasing the degree of substitution. Examples 14-16 arepolymers that do not fulfil our criteria. Table 4(B) shows that thedrying solvent has some effect on the absorption characteristics of thecarboxylated polymers but that this is not as marked as with thenitrogen containing polymers. Table 4C shows that the carboxylic acidform of the polymers do not satisfy our criteria of invention but aredisclosed since they give rise to the ionic form which falls within ourdefinition.

    ______________________________________                                        Preparation of Examples Shown in Table 4                                      Example                                                                              Preparation                                                            ______________________________________                                         1     Excess SO.sub.3 --pyridine complex in DMF*, 100°, 35                   hours on appropriate alcohol                                            2     Chlorosulphonic acid in ether, RT, 1-2 hours on appro-                        priate alcohol                                                         3,4,5  Excess aqueous Na.sub.2 SO.sub.3, reflux, 55 hours on appropriate             cationic polymer                                                        6     Excess m-chloroperbenzoic acid in trichloroethane,                            60°, 15 hours on appropriate aldehyde                           7,8,10 Excess concentrated HNO.sub.3, 100°, 5-6 hours on appro-               priate alcohol                                                         9      Excess alkaline KMnO.sub.4, 100°, 1 hour on appropriate                alcohol                                                                11     Hydrolysis of 2-ethylhexyl acrylate in 90% H.sub.2 SO.sub.4, RT,              2 weeks                                                                12     Hydrolysis of n-butyl methacrylate in concentrated                            H.sub.2 SO.sub.4, RT, 5.5 days                                         13     Hydrolysis of t-butyl acrylate in 90% H.sub.2 SO.sub.4, RT,                   3 days                                                                 14-16  Standard porous polymer preparations                                   17     Acidic form of Example 9                                               18     Acidic form of Example 8                                               19     Similar to acidic form of Example 6                                    ______________________________________                                         *DMF = dimethyl formamide                                                

PREPARATION OF ETHOXYLATED DERIVATIVES

In the preparation currently employed, standard chloromethyl styrenepolymer is treated with the anionic form of a polyethylene glycol inexcess polyethylene glycol as solvent. In some instances, the glycolitself is too viscous at room temperature to enter the pores of thepolymer, even under vacuum, in which case the glycol is heated to reduceits viscosity to a point where the polymer can be vacuum filled. Thereactants are then heated at 90°-100° C. for periods up to 30 hours. Thesolids are recovered, washed with water until glycol and alkali free,then washed with methanol and dried. Alternatively, the methanolsaturated polymer can be solvent exchanged for hexane and then dried. Ineither case, an open expanded, rubbery, elastic solid is recovered whichcan be used for liquid absorption.

Other processes which can be employed include those in which the polymeris treated with the glycol anion in a suitable inert solvent, especiallywhere the glycol has such a high molecular weight that it is tooviscous/solid to enter the polymer pores even under heating/vacuum.Other standard ethoxylation processes, such as the use of ethylene oxidefor the ethoxylation of hydroxy or carboxy functionalised polymers, canalso be used.

    ______________________________________                                        Preparation of Examples Shown in Table 5                                      Example Preparation                                                           ______________________________________                                        1       PEG 400 anion in PEG 400 as solvent, 100°,                             30 hours on chloromethyl polymer                                      2       PEG 200 anion in PEG 200 as solvent, 100°,                             25 hours on chloromethyl polymer                                      3       Diethylene glycol anion in diethylene glycol                                  as solvent, 100°, 25 hours                                     4-6     PEG 200 anion in PEG 200 as solvent, 100°,                             25 hours on chloromethyl polymer                                      7       Standard porous polymer preparation                                   Polystyrene                                                                   polymer                                                                       ______________________________________                                         *PEG -- polyethylene glycol                                              

Examples are given in Table 5. Examples 1-3 show the effect ofdecreasing EO chain length. Examples 2 and 4 show the effect of voidvolume. Examples 5, 6 and 2 show the effect of crosslinking level.Example 7 again shows that the materials disclosed in European PatentApplication No. 60 138 fall outside this invention.

ION EXCHANGE PROPERTIES

The ionic polymers of this invention can also be used as efficient ionexchange resins by virtue of their high porosity and will function inthis capacity at a much greater rate than currently marketed ionexchange beads. This can be readily visualised by the rapiddecolourisation of dilute solutions of ionic dyes. For example, a dilutesolution of sodium fluorescein was prepared. To 10 ml of this solutionwas added 50 mg of a dried cationic polymer of this invention (Table 1,Example 1) and the polymer allowed to swell in the aqueous liquor. Tofurther 10 ml samples of this dye solution was added

(a) 100 mg (about the same exchange capacity as above) and

(b) 500 mg (about 5 times the exchange capacity as the above) of wetcommercial resin beads (Amberlite IRA 400, containing about 50% water).

The mixtures were shaken for 30 seconds after which it could be seenthat the liquors containing the commercial ion exchange beads were stillintensely coloured whereas the liquor containing our porous polymer wasvirtually colourless and that the polymer was now coloured orange by theabsorbed dye.

Similarly a solution containing 100 ppm Fe³⁺ ions, present as theintensely red coloured thiocyanate complex was prepared. To 10 ml ofthis solution was added 10 mg of a dried carboxylated polymer (sodiumform) of this invention (Table 4, Example 7) and the polymer allowed toswell in the aqueous phase. To further 10 ml samples of the ferricsolution was added (a) 30 mg (about the same exchange capacity as above)and (b) 300 mg (about 10 times the exchange capacity as above) ofcommercially available exchange resin (Zeo Karb 225, Na⁺ form containingH₂ O). The mixtures were allowed to stand at RT over several hours withintermittent shaking. The sample containing 30 mg of commercial resinshowed little change in colour over 4 hours whereas the samplecontaining 300 mg of commercial resin showed a loss of colour over 2hours while still being distinctly coloured. By contrast, the mixturecontaining our porous polymer showed a significant loss of colour afterseveral minutes and was virtually colourless in one hour.

A 50 ml burette was packed with 0.28 g of preswollen porous polymer(Table 1, Example 1) and through this was passed a solution of 0.1%dodecylbenzene sulphonate at a flow rate of 2 ml per minute. The aqueousliquor passing out of the column was monitored using UV spectroscopy.Initially, the aqueous liquor contains less than 0.005% detergent bycomparison with the UV spectrum of control solutions and only afterabout 290 ml of liquor had passed through the column did theconcentration of detergent start to increase. Using the same burette,about 7 g of commercial resin beads (Amberlite IRA 400) were required inthe column to reduce the detergent level to less than 0.005% at the samerate of flow.

                                      TABLE 1                                     __________________________________________________________________________     ##STR9##                                                                                                                 Liquid Absorption                                                  Pore Level of                                                                            (g liquid/g polymer)                                        Crosslinking                                                                         Volume                                                                             Substitution                                                                            10% Oleic                                                                             10% NaCl              Example                                                                            Polymer              Level (%)                                                                            (cc/g)                                                                             (%)   H.sub.2 O                                                                         NaCl                                                                              Acid                                                                              H.sub.2 O             __________________________________________________________________________                                                            Ratio                 (A) All polymers dried from methanol                                          1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    49.0                                                                              50.5                                                                              <1  1.03                  2    R.sub.1 = R.sub.2 = R.sub.3 = C.sub.2 H.sub.5                                                 x = Cl                                                                             5      30   85    53.5                                                                              40.9                                                                              <1  0.76                  3    R.sub.1 = R.sub.2 = CH.sub.3 R.sub.3 = C.sub.6 H.sub.13                                       x =  Cl                                                                            5      30   80    27.2                                                                              22.9                                                                              1.05                                                                              0.84                  4    R.sub.1 = R.sub.2 = CH.sub.3 R.sub.3 = C.sub.10 H.sub.21                                      x = Cl                                                                             5      30   70    0*  0*  --  --                    5    unsubstituted polystyrene                                                                          5      30   0     0*  0*  26.0                                                                              --                    6    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   27     1.5                                                                              1.06                                                                              2.7 0.70                  7    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   58    20.5                                                                              5.5 <1  0.27                  8    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   71.5  38.0                                                                              47.1                                                                              <1  1.24                  1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    49.0                                                                              50.5                                                                              <1  1.03                  9    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = OH                                                                             5      30   71.5  51.5                                                                              46.1                                                                              <1  0.89                  8    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   71.5  38.0                                                                              47.1                                                                              <1  1.24                  1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    49.0                                                                              50.5                                                                              <1  1.03                  10   R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = NO.sub.3                                                                       5      30   85    36.9                                                                              29.4                                                                              <1  0.79                  11   R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5       9   88.5  25.2                                                                              21.8                                                                              1.4 0.86                  1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    49.0                                                                              50.5                                                                              <1  1.03                  12   R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             2      30   86.5  18.3                                                                              4.8 <1  0.26                  1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    49.0                                                                              50.5                                                                              <1  1.03                  13   R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             10     30   80.5  39.0                                                                              42.5                                                                              1.25                                                                              1.09                  (B) All polymers dried from hexane                                            14   R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   70    24.0                                                                              25.2                                                                              3.6 1.05                  1    R.sub.1 = R.sub.2 = R.sub.3 = CH.sub.3                                                        x = Cl                                                                             5      30   85    27.0                                                                              37.3                                                                              9.0 1.38                  2    R.sub.1 = R.sub.2 = R.sub.3 = C.sub.2 H.sub.5                                                 x = Cl                                                                             5      30   85    0*  0*  18.0                                                                              --                    3    R.sub.1 = R.sub.2 = CH.sub.3 R.sub.3 =  C.sub.6 H.sub.13                                      x = Cl                                                                             5      30   80    0*  0*  4.3 --                    __________________________________________________________________________     *Floats on the liquid                                                    

                                      TABLE 2                                     __________________________________________________________________________     ##STR10##                                                                                                          Liquid Absorption                                                  Pore Level of                                                                            (g liquid/g polymer)                                        Crosslinking                                                                         Volume                                                                             Substitution                                                                           10% Oleic                                                                             10% NaCl                     Example                                                                            Polymer        Level (%)                                                                            (cc/g)                                                                             (%)** H.sub.2 O                                                                        NaCl                                                                              Acid                                                                              H.sub.2 O                    __________________________________________________________________________                                                     Ratio                        (A) All polymers dried from methanol                                          1    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5      30   85    35.5                                                                             27.2                                                                              1.1 0.76                         2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              5      30   90    53.0                                                                             41.2                                                                              <1  0.77                         3    R.sub.1 = R.sub.2 = C.sub.4 H.sub.9                                                    x = Cl                                                                              5      30   74    0* 0*  5.8 --                           4    unsubstituted polystyrene                                                                    5       30   0    0* 0*  26.0                                                                              --                           5    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5      30   39    20.5                                                                             4.95                                                                              5.4 0.24                         6    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = SO.sub.4                                                                        5      30   39    11.2                                                                             8.6 4.9 0.77                         1    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5      30   85    35.5                                                                             27.2                                                                              1.1 0.76                         7    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = SO.sub.4                                                                        5      30   85    19.5                                                                             26.5                                                                              <1.0                                                                              1.36                         8    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = lactate                                                                         5      30   85    16.1                                                                             9.6 16.3                                                                              0.59                         10   R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5       9     83.5                                                                              26.2                                                                             15.4                                                                              1.8 0.59                         1    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5      30   85    35.5                                                                             27.2                                                                              1.1 0.76                         11   R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              2      30     78.5                                                                              structural collapse on drying           11'  R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              2      30     78.5                                                                              6.4                                                                              4.8 <1  0.75                         2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              5      30   90    53.0                                                                             41.2                                                                              <1  0.77                         13   R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              10     30   73    30.8                                                                             41.2                                                                              2.7 0.75                         (B) All polymers dried from hexane                                            1    R.sub.1 = R.sub.2 = CH.sub.3                                                           x = Cl                                                                              5      30   85    40.0                                                                             25.0                                                                              12.2                                                                              0.62                         2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = Cl                                                                              5      30   90    58.5                                                                             23.6                                                                              13.8                                                                              0.40                         3    R.sub. 1 = R.sub.2 = C.sub.4 H.sub.5                                                   x = Cl                                                                              5      30   74    0* 0*  11.2                                                                              --                           9    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                    x = oleate                                                                          5      30   85    0* 0*  60.0                                                                              --                           __________________________________________________________________________     *Floats on the liquid                                                         **Level of substitution in parent amine                                       11 and 11' are identical materials dried under different conditions      

                                      TABLE 3                                     __________________________________________________________________________     ##STR11##                                                                                                        Liquid Absorption                                                  Pore Level of                                                                            (g liquid/g polymer)                                        Crosslinking                                                                         Volume                                                                             Substitution                                                                           10% Oleic                                                                             10% NaCl                       Example                                                                            Polymer      Level (%)                                                                            (cc/g)                                                                             (%)** H.sub.2 O                                                                        NaCl                                                                              Acid                                                                              H.sub.2 O                      __________________________________________________________________________                                                   Ratio                          (A) All polymers dried from methanol                                          1    R.sub.1 = R.sub.2 = CH.sub.3                                                               5      30   85    52.5                                                                             36.7                                                                              <44 0.70                           2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        5      30   85    51.2                                                                             56.7                                                                              <1  1.11                           3    R.sub.1 = R.sub.2 = C.sub.4 H.sub.9                                                        5      30   74    0* 0*  25.5                                                                              --                             4    unsubstituted polystyrene                                                                  5      30    0    0* 0*  26.0                                                                              --                             5    R.sub.1 =  R.sub.2 = CH.sub.3                                                              5      30   39    22.0                                                                             18.6                                                                              12.8                                                                              0.84                           1    R.sub.1 = R.sub.2 = CH.sub.3                                                               5      30   85    52.5                                                                             36.7                                                                              <1  0.70                           6    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        5       9     83.5                                                                              24.1                                                                             9.8 <1  0.41                           2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        5      30   85    51.2                                                                             56.7                                                                              <1  1.11                           7    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        2      30     78.5                                                                              structural collapse on drying              7'  R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        2      30     78.5                                                                              19.8                                                                             5.4 <1  0.27                           2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        5      30   85    51.2                                                                             56.7                                                                              <1  1.11                           8    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        10     30   73    13.0                                                                             27.0                                                                              14.9                                                                              2.0                            (B) All polymers dried from hexane                                            1    R.sub.1 = R.sub.2 = CH.sub.3                                                               5      30   85    24.2                                                                             35.4                                                                              14.2                                                                              1.46                           2    R.sub.1 = R.sub.2 = C.sub.2 H.sub.5                                                        5      30   85    36.2                                                                             46.3                                                                              71.5                                                                              1.28                           3    R.sub.1 = R.sub.2 = C.sub.4 H.sub.9                                                        5      30   74    0* 0*  16.2                                                                              --                             __________________________________________________________________________     *floats on the liquid                                                         **level of substitution in parent amine                                       7 and 7' are identical materials dried under different conditions        

                                      TABLE 4                                     __________________________________________________________________________     ##STR12##                                                                                                           Liquid Absorption                                                  Pore Level of                                                                            (g liquid/g polymer)                                        Crosslinking                                                                         Volume                                                                             Substitution                                                                           10% Oleic                                                                             10% NaCl                    Example                                                                            Polymer         Level (%)                                                                            (cc/g)                                                                             (%)   H.sub.2 O                                                                        NaCl                                                                              Acid                                                                              H.sub.2 O                   __________________________________________________________________________                                                      Ratio                       (A) All polymers dried from methanol                                           1   I, P = H, Z = CH.sub.2 OSO.sub.3 Na                                                           5      30   70    29.1                                                                             25.5                                                                              5.2 0.87                         2   I, P = H, Z = CH.sub.2 OSO.sub.3 Na                                                           5      30   50    15.0                                                                             11.2                                                                              9.0 0.75                         3   I, P = H, Z = CH.sub.2 SO.sub.3 Na                                                            5      30   85    49 50  <1  1.02                         4   I, P = H, Z = CH.sub.2 SO.sub.3 Na                                                            5      30   58    26.4                                                                             21.2                                                                              <1  0.80                         5   I, P = H, Z = CH.sub.2 SO.sub.3 Na                                                            5      30   30    3.5                                                                              6.2 2.6 1.77                         6   I, P = H, Z = COONa                                                                           5      30   50    14.8                                                                             22.8                                                                              9.0 1.54                         7   I, P = NO.sub.2, Z = COONa                                                                    5      30     86.5                                                                              49.9                                                                             6.2 <1  0.12                         8   I, P = NO.sub.2, Z = COONa                                                                    5      30   95    69.8                                                                             14.9                                                                              <1  0.24                         9   I, P = H, Z = COONa                                                                           5      30   100   80.3                                                                             51.8                                                                              <1  0.64                        10   I, P = NO.sub.2, Z = COONa                                                                    5       9   70    29.8                                                                             3.0 <1  0.10                        11   II, R.sub.5 = H, Z = COONa (50/50                                                             5      30   30    15.0                                                                             11.6                                                                              5.3 0.77                             copolymer with styrene)                                                  12   II, R.sub.5 = CH.sub.3, Z = COONa                                                             5      30   62    38.3                                                                             37.3                                                                              13.8                                                                              0.97                        13   II, R.sub.5 = H, Z = COONa                                                                    5      30   75    53.5                                                                             32.5                                                                              <1  0.61                        14   II, R.sub.5  = CH.sub.3, Z = COOC.sub.4 H.sub.9                                               5      30   90    0* 0*  2.3 --                          15   II, R.sub.5 = H, Z = COOC.sub.4 H.sub.9                                                       5      30   90    0* 0*  8.2 --                          16   unsubstituted polystyrene                                                                     5      30    0    0* 0*  26.0                                                                              --                          (B) All polymers dried from hexane                                             5   I, P = H, Z = CH.sub.2 SO.sub.3 Na                                                            5      30   30    2.4                                                                              5.0 1.8 2.08                         4   I, P = H, Z = CH.sub.2 SO.sub.3 Na                                                            5      30   58    20.2                                                                             31.5                                                                              1.85                                                                              1.56                        13   II, R.sub.5 = H, Z = COONa                                                                    5      30   75    45.3                                                                             42.4                                                                              5.5 0.94                        11   II, R.sub.5 = H, Z = COONa (50/50                                                             5      30   30    17.3                                                                             16.0                                                                              10.3                                                                              0.92                             copolymer with styrene)                                                  15   II, R.sub.5 = H, Z = COOC.sub.4 H.sub.9                                                       5      30   90    0* 0*  8.2 --                          (C) Acid form of the carboxylated polymers, dried from hexane                 17   I, P = H, Z = COOH                                                                            5      30   100   0* 0*  1.2 --                          18   I, P = NO.sub.2, Z = COOH                                                                     5      30   95    0* 0*  4.7 --                          19   I, P = H, Z = COOH                                                                            5      30   60    0* 0*  11.0                                                                              --                          __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________     ##STR13##                                                                                                  Liquid Absorption                                                  Pore Level of                                                                            (g liquid/g polymer)                                        Crosslinking                                                                         Volume                                                                             Substitution                                                                           10% Oleic                                                                             10% NaCl                             Example                                                                            Polymer                                                                              Level (%)                                                                            (cc/g)                                                                             (%)   H.sub.2 O                                                                        NaCl                                                                              Acid                                                                              H.sub.2 O Ratio                      __________________________________________________________________________    (A) All polymers dried from methanol                                          1    n = 8-9                                                                              5      30   90    18.0                                                                             15.4                                                                              12.6                                                                              0.85                                 2    n = 4  5      30   **    8.4                                                                              9.7 6.9 1.15                                 3    n = 2  5      30   **    7.0                                                                              7.4 7.4 1.06                                 4    n = 4  5       9   **     6.15                                                                            6.9 3.7 1.12                                 2    n = 4  5      30   **    8.4                                                                              9.7 6.9 1.15                                 5    n = 4  2      30   **    3.0                                                                               2.84                                                                             1.0 0.95                                 2    n = 4  5      30   **    8.4                                                                              9.7 6.9 1.15                                 6    n = 4  10     30   **    16.3                                                                             17.6                                                                              16.1                                                                              1.08                                 7    unsubstituted                                                                        5      30    0    0* 0*  26.0                                                                              --                                        polystyrene                                                              __________________________________________________________________________     *floats on the liquid                                                         **not determined                                                         

We claim:
 1. A porous, homogeneous, cross-linked polymeric materialhaving interconnected cavities or chambers of micron dimensions whosetotal pore volume is greater than 95% (20 cc/g), said material formedfrom a water-in-oil emulsion, said emulsion containing at least 95% byweight water, the material having a dry density of less than 0.15 g/ccand comprising at least 30% by weight of chloromethyl styrene residuescrosslinked with a di-functional agent.
 2. A polymeric materialaccording to claim 1 wherein said emulsion further comprises asurfactant in an amount greater than 20% by weight.